Added x0uid Spotify Ad Block List

[s0kil]

Fixes #343

[crssi]

This is nice... can you drop the https://github.com/nextdns/metadata/blob/master/privacy/blocklists/chef-koch-spotify.json in favor of this one.

See: #340 (comment)

[romaincointepas]

I don't get why this blocklist has a separate whitelist (vs. a combined final hosts file).

x0uid/SpotifyAdBlock#24 is not reassuring.

[s0kil]

@crssi Seems like that should be done in a separate PR.

[crssi]

Actually I do not use Spotify at all, but I do think any project should not support plagiarisms and in this case CHEF-KOCH.
It would be a shame that supporting plagiarism would drop a shadow onto reliability. 😞

[romaincointepas]

@x0uid would you be open to providing a unified blocklist that automatically removes the domains from the whitelist from the main list?

I may be missing something but I don't get the duo blocklist with false positives then separate whitelist.